The crystal structures of 8-phenoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride, C16H21... more The crystal structures of 8-phenoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride, C16H21N2O2(+)·Cl(-), (I), and 8-methoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride monohydrate, C11H19N2O2(+)·Cl(-)·H2O, (II), recently reported by Carafa, Mesto & Quaranta [Eur. J. Org. Chem. (2011), pp. 2458-2465], are analysed and discussed with a focus on crystal interaction assembly. Both compounds crystallize in the space group P2(1)/c. The crystal packings are characterized by dimers linked through π-π stacking interactions and intermolecular nonclassical hydrogen bonds, respectively. Additional intermolecular C-H···Cl interactions [in (I) and (II)] and classical O-H···Cl hydrogen bonds [in (II)] are also evident and contribute to generating three-dimensional hydrogen-bonded networks.
The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists t... more The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite (KBi) in degrading pentachlorophenol (PCP) through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi-PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner-sphere complex between the phenolic group of the organic molecules and the structural Mn(IV). This is indicated by the changes induced in birnessite MnO(6) layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn(IV) reduction, the consequent formation of Mn(III) and new vacancies, and free Mn(2+) ions release. The PCP degradation extent is limited by the presence of chloro-substituents on the aromatic ring.
The crystal chemistry of Ti-rich trioctahedral micas of plutonic origin, cropping out at Black Hi... more The crystal chemistry of Ti-rich trioctahedral micas of plutonic origin, cropping out at Black Hill (South Australia) has been investigated by combining electron microprobe analysis, single crystal X-ray diffraction, Mössbauer spectroscopy and X-ray photoelectron spectroscopy. ...
ABSTRACT The determination of the oxidation state and structural role of transition metals in min... more ABSTRACT The determination of the oxidation state and structural role of transition metals in minerals is a crucial challenge. XPS has proven to have a great potential in probing the site distribution and chemical states of Fe and Ti transition elements, provided that the right method to process the spectra is used. XPS spectra of these elements have the 2p core level region usually rich of features but the choice of the method for background removing can seriously affect the results of the quantitative analysis. Single crystals of brookite (TiO2) and natural micas (phlogopites) are investigated to examine the effect of background subtraction on Ti2p and Fe2p signals. The backgrounds used are: the “Linear” background; the traditional “Shirley” background; three different Tougaard-like backgrounds; and the more recent “shape parameter, κ” method. In the case of the studied natural micas, the Fe chemical state proportion (Fe2+/Fetot) obtained with the corrected spectra varies by 10%. It is shown that TiO2 oxides are not suitable as standard for octahedral Ti4+ signal in the studied micas. The “shape parameter, κ” method proves to provide supplementary information useful for a full interpretation of XPS signals.
The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists t... more The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite (KBi) in degrading pentachlorophenol (PCP) through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi-PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner-sphere complex between the phenolic group of the organic molecules and the structural Mn(IV). This is indicated by the changes induced in birnessite MnO(6) layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn(IV) reduction, the consequent formation of Mn(III) and new vacancies, and free Mn(2+) ions release. The PCP degradation extent is limited by the presence of chloro-substituents on the aromatic ring.
IOP Conference Series: Materials Science and Engineering, 2010
Page 1. The role of SIMS in the investigation of the complex crystal chemistry of mica minerals T... more Page 1. The role of SIMS in the investigation of the complex crystal chemistry of mica minerals This article has been downloaded from IOPscience. ... Before the advent of SIMS, formula recalculation of mica was performed using different normalisation schemes. ...
The crystal structures of 8-phenoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride, C16H21... more The crystal structures of 8-phenoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride, C16H21N2O2(+)·Cl(-), (I), and 8-methoxycarbonyl-1,8-diazabicyclo[5.4.0]undec-7-enium chloride monohydrate, C11H19N2O2(+)·Cl(-)·H2O, (II), recently reported by Carafa, Mesto & Quaranta [Eur. J. Org. Chem. (2011), pp. 2458-2465], are analysed and discussed with a focus on crystal interaction assembly. Both compounds crystallize in the space group P2(1)/c. The crystal packings are characterized by dimers linked through π-π stacking interactions and intermolecular nonclassical hydrogen bonds, respectively. Additional intermolecular C-H···Cl interactions [in (I) and (II)] and classical O-H···Cl hydrogen bonds [in (II)] are also evident and contribute to generating three-dimensional hydrogen-bonded networks.
The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists t... more The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite (KBi) in degrading pentachlorophenol (PCP) through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi-PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner-sphere complex between the phenolic group of the organic molecules and the structural Mn(IV). This is indicated by the changes induced in birnessite MnO(6) layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn(IV) reduction, the consequent formation of Mn(III) and new vacancies, and free Mn(2+) ions release. The PCP degradation extent is limited by the presence of chloro-substituents on the aromatic ring.
The crystal chemistry of Ti-rich trioctahedral micas of plutonic origin, cropping out at Black Hi... more The crystal chemistry of Ti-rich trioctahedral micas of plutonic origin, cropping out at Black Hill (South Australia) has been investigated by combining electron microprobe analysis, single crystal X-ray diffraction, Mössbauer spectroscopy and X-ray photoelectron spectroscopy. ...
ABSTRACT The determination of the oxidation state and structural role of transition metals in min... more ABSTRACT The determination of the oxidation state and structural role of transition metals in minerals is a crucial challenge. XPS has proven to have a great potential in probing the site distribution and chemical states of Fe and Ti transition elements, provided that the right method to process the spectra is used. XPS spectra of these elements have the 2p core level region usually rich of features but the choice of the method for background removing can seriously affect the results of the quantitative analysis. Single crystals of brookite (TiO2) and natural micas (phlogopites) are investigated to examine the effect of background subtraction on Ti2p and Fe2p signals. The backgrounds used are: the “Linear” background; the traditional “Shirley” background; three different Tougaard-like backgrounds; and the more recent “shape parameter, κ” method. In the case of the studied natural micas, the Fe chemical state proportion (Fe2+/Fetot) obtained with the corrected spectra varies by 10%. It is shown that TiO2 oxides are not suitable as standard for octahedral Ti4+ signal in the studied micas. The “shape parameter, κ” method proves to provide supplementary information useful for a full interpretation of XPS signals.
The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists t... more The existence of a lot of worldwide pentachlorophenol-contaminated sites has induced scientists to concentrate their effort in finding ways to degrade it. Therefore, an effective tool to decompose it from soil mixtures is needed. In this work the efficiency of the phyllomanganate birnessite (KBi) in degrading pentachlorophenol (PCP) through mechanochemical treatments was investigated. To this purpose, a synthesized birnessite and the pollutant were ground together in a high energy mill. The ground KBi-PCP mixtures and the liquid extracts were analyzed to demonstrate that mechanochemical treatments are more efficient in removing PCP than a simple contact between the synthesized birnessite and the pollutant, both in terms of time and extent. The mechanochemically induced PCP degradation mainly occurs through the formation of a surface monodentate inner-sphere complex between the phenolic group of the organic molecules and the structural Mn(IV). This is indicated by the changes induced in birnessite MnO(6) layers as a consequence of the prolonged milling with the pollutant. This mechanism includes the Mn(IV) reduction, the consequent formation of Mn(III) and new vacancies, and free Mn(2+) ions release. The PCP degradation extent is limited by the presence of chloro-substituents on the aromatic ring.
IOP Conference Series: Materials Science and Engineering, 2010
Page 1. The role of SIMS in the investigation of the complex crystal chemistry of mica minerals T... more Page 1. The role of SIMS in the investigation of the complex crystal chemistry of mica minerals This article has been downloaded from IOPscience. ... Before the advent of SIMS, formula recalculation of mica was performed using different normalisation schemes. ...
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